Abstract
This paper reports the effective surface effect of porous inorganic membranes on improving the emulsion separations (i.e., perm-selective extraction of either oil phase or aqueous phase from the emulsions). A novel tubular form of superwetting, porous, stainless steel/ceramic membranes were demonstrated for enabling continuous separations of oil-water emulsions, extracting either oil phase or aqueous phase from the flowing emulsions. The superhydrophobic membranes consist of macroporous (4 μm) stainless-steel SS434 tube with inner wall surface modified with superhydrophobicity (>150° contact angle) via perfluoro-silane grafting functionalization. The (super)hydrophilic membranes consist of 4-μm porous stainless-steel SS434 tube without/with inner wall coated with nanoporous alumina (6 nm average pore size), the surface of which was further modified with superhydrophilicity via Hydrophil-S solution deposition. With the cross-flow membrane filtration setup, the surface-engineered tubular membranes were studied for perm-selective extraction of aqueous or oil phase from oil-water emulsions (water-in-oil W/O and oil-in-water O/W) that are relevant to a real industrial biodiesel (FAME) production process. The superhydrophobic membrane (4 μm pore size) has demonstrated capability of extracting nearly 100% pure oil while rejecting water phase when either W/O or O/W emulsions were tested as feed. The superhydrophobic membrane showed distinct advantage of 2-orders-of-magnitude-higher flux extraction of oil at 100 times higher "break-through" pressures. On the other hand, the super/hydrophilic nanoporous membranes (6 nm) have shown selective water permeation (separation factor up to 35) when biodiesel-relevant W/O emulsions were tested. Finally, the membrane function is discussed from the perspective of improving industrial biodiesel processing yield by overcoming equilibrium limitations during the biodiesel formation reactions. Future work on in situ reaction-separation experiments are envisioned.
| Original language | English |
|---|---|
| Pages (from-to) | 1114-1122 |
| Number of pages | 9 |
| Journal | Industrial and Engineering Chemistry Research |
| Volume | 58 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jan 16 2019 |
Funding
*Tel.: +1-865-684-7576. E-mail: [email protected]. ORCID Michael Z. Hu: 0000-0002-2341-5298 Notes This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The U.S. Government retains copyright and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for U.S. Government purposes. The Department of Energy (DOE) will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). The authors declare no competing financial interest.
| Funders | Funder number |
|---|---|
| Bioenergy Technology Office | |
| U.S. Department of Energy |
